SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5ea6591ab48dff2ef52006feae425ea00dc8e7b1b3078c33833f1da4b75a961' 
  AND token = '6Tggw2vJzkbnWmnl1CY0RhDkpA/LYKtvvO8zPRPQWvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}